These days, demand for flat panel displays has been increased with a shift to the highly-networked information society. As such displays, a non-self-luminous liquid crystal display (LCD), a self-luminous plasma display (PDP), an inorganic electroluminescence (inorganic EL) display, an organic electroluminescence (organic EL) display (for example, Patent Literature 1), etc. are known. Among these displays, especially an organic EL display attracts attention because an organic EL display is a self-luminous display and has features of a wide viewing angle, high contrast, high speed of response, and the like, which features are not found in an LCD.
With reference to FIG. 8, the following discusses a general organic EL device which is applied to an electronic device such as an organic EL display. FIG. 8 is a cross sectional view schematically illustrating a configuration of a substantial part of a conventional organic EL device.
As illustrated in FIG. 8, an organic EL device 100 includes, as organic EL elements 110, an organic EL element 110a emitting red light, an organic EL element 110b emitting green light, and an organic EL element 110c emitting blue light. The organic EL element 110a, the organic EL element 110b, and the organic EL element 110c constitute one unit arranged in a matrix pattern, and luminescence regions of the organic EL elements 110 are defined by a dividing wall (bank) 117. Note that, each of the organic EL elements 110 includes a lower electrode (anode) 114, a hole transport layer 118, a light-emitting layer 119, an upper electrode (cathode) 120, and the like.
More specifically, in the organic EL device 100, a plurality of TFTs (Thin Film Transistor) 112 which serve as driving elements are provided on an insulation substrate 111 made of a glass substrate and the like. An interlayer insulation film 113 made of silicon oxide (SiO2), silicon nitride (SiN), and the like is provided on the entire insulation substrate 111 so as to cover the TFTs 112, and the lower electrodes 114 made of an electrode material with large work function such as ITO (Indium Tin Oxide) and IZO (Indium Zinc Oxide) are provided thereon in such a manner as to correspond to the TFTs 112, respectively. Note that, the interlayer insulation film 113 has a plurality of contact holes 115, depending on the number of the TFTs 112, and the lower electrodes 114 penetrating the interlayer insulation film 113 are electrically connected to the TFTs 112 in the contact holes 115, respectively.
A plurality of edge covers 116 made of an insulation material such as silicon oxide (SiO2) are provided so as to cover boundaries between the adjacent lower electrodes 114, and the dividing wall 117 made of an organic resin material such as an acrylic resin is formed thereon. Note that, the dividing wall 117 is formed by applying an acrylic material by spin coating, and exposing and developing the acrylic material by photolithography.
On the edge covers 116 in the respective spaces defined by the dividing wall 117, the hole transport layers 118 made of oxide such as vanadium oxide (V2O5) and molybdenum oxide (MoO2) are provided, and a light-emitting layer 119a emitting red light, a light-emitting layer 119b emitting green light, and a light-emitting layer 119c emitting blue light are provided thereon as light-emitting layers 119 respectively. That is, the dividing wall 117 divides the light-emitting layers 119 of the plurality of organic EL elements 110. The upper electrode (cathode) 120 is provided on the entire insulation substrate 111 so as to cover the light-emitting layers 119 and the dividing wall 117. Specifically, the upper electrode 120 spreads over the areas of the light-emitting layers 119 defined by the dividing wall 117 and over the dividing wall 117 so that the upper electrode 120 is shared in common by a plurality of the organic EL elements 110.
On the upper electrode 120, a sealing resin 121 is adhered, and a sealing substrate 122 made of a glass substrate, etc. is provided thereon. In this way, the organic EL elements 110 are sealed by attaching the insulation substrate 111 to the sealing substrate 122. This configuration can prevent the organic EL elements 110 from being damaged by oxygen and water.